#!usr/bin/env python  
# -*- coding:utf-8 -*-
""" 
@author:robot
@file: n_stage.py 
@version:
@time: 2023/12/21
              4
            2/ \1
           2     3
           ^   2/ \1
           2   1   2
               ^   ^
               1    2

"""


def climb_stairs(n):
    count = [0, 1, 2]
    for i in range(3, n + 1):
        count.append(count[i - 1] + count[i - 2])
    return count[n]


print(climb_stairs(10))
print(climb_stairs(11))
print(climb_stairs(12))
